All the states' official election boards have certified their votes. All the lower courts and states' supreme courts agreed.
There are no constitutional arguments to be made, although the Google search constitutional scholars' will tell you otherwise.
The only path he has, is for the state houses to invalidate voters wishes, and send electoral voters who will cast their votes for Trump. That's no longer a scenario, because Governors of these states certified results.
Trump was all excited today, because an Alabama Congressman said he's going to challenge the electoral college vote, when Congress meets in a joint session on January 6th, 2021, to certify the Dec 14 electoral college vote.